Power drive aquatic scrubbing devices are well-known in the art, typical examples being shown in U.S. Pat. No. 4,314,521, Lundberg and U.S. Pat. No. 4,084,535, Rees. These devices, while admirable for their intended purpose, require the personal attendance of a diver for controlling the movements of the device, and, for manipulating it onto and over the surface to be cleaned. Clearly, the involvement of a diver results in an increase in the expense of the cleaning operation. Additionally, the apparatus involves brushes rotating at considerable speed and which constitute a hazard to the diver and are difficult to handle.
Various devices have been proposed for magnetic attachment to a ferro-magnetic surface, and which can be moved over that surface, such surfaces including the ferro-magnetic hulls of ships. The devices are primarily employed in maintenance of the ship's hull, including painting and scraping at the time the ship is dry-docked. Typical examples of such devices are to be found in U.S. Pat. No. 3,960,229, Shio, and U.S. Pat. No. 2,104,062, Temple. Such devices are limited in their use to movement over a ship's hull exclusively in a linear direction with a rolling motion, and must be removed from the hull and repositioned for them to traverse an adjacent area. Tibbling, U.S. Pat. No. 3,609,612, teaches a magnetic device having steerable rollers in order that it may change direction when moving over a ferro-magnetic surface, such as a ship's hull. This device, however, has no practical utility in the cleaning of the ship's hull.